Definition/General

Introduction:
-Phyllodes tumor with glassy cell carcinoma is an exceptionally rare malignant phyllodes tumor where the stromal component contains glassy cell carcinoma, characterized by cells with ground-glass cytoplasm
-This represents a unique form of heterologous phyllodes tumor.
Origin:
-Develops from intralobular breast stroma with differentiation toward glassy cell carcinoma
-May arise through specific metabolic alterations in stromal cells leading to characteristic cytoplasmic appearance.
Classification:
-WHO Classification categorizes this as malignant phyllodes tumor with heterologous elements
-Glassy cell carcinoma component shows characteristic ground-glass cytoplasm and specific immunoprofile.
Epidemiology:
-Exceptionally rare with fewer than 5 cases reported worldwide
-Peak age 40-60 years
-Female predominance
-Clinical behavior similar to other high-grade heterologous phyllodes tumors.

Clinical Features

Presentation:
-Large, rapidly growing breast mass
-Usually presents as painless mass that becomes symptomatic with growth
-May show rapid enlargement over months.
Symptoms:
-Progressive breast enlargement
-Breast asymmetry
-May become painful with rapid growth
-Skin changes in advanced cases
-Constitutional symptoms rare.
Risk Factors:
-Previous phyllodes tumor history
-Middle age
-No specific environmental or genetic risk factors identified
-Possible association with hormonal factors.
Screening:
-No specific screening available
-Clinical examination for masses
-Imaging with mammography and ultrasound
-Tissue diagnosis essential for confirmation.

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Gross Description

Appearance:
-Large, well-circumscribed to partially circumscribed mass
-Cut surface shows gray-white areas with possible yellow or glassy appearance
-Firm consistency.
Characteristics:
-Size typically >4 cm (range 3-12 cm)
-Variable consistency
-May have characteristic glassy or translucent areas
-Focal necrosis possible.
Size Location:
-Can occur in any breast quadrant
-Usually involves significant breast tissue
-Unilateral presentation typical
-Local extension possible.
Multifocality:
-Typically unifocal mass
-Multifocal glassy areas within tumor possible
-Satellite lesions rare
-Local invasion in advanced cases.

Microscopic Description

Histological Features:
-Biphasic tumor with epithelial and mesenchymal components
-Glassy cell carcinoma areas show cells with characteristic ground-glass cytoplasm
-Large cells with distinct cell borders.
Cellular Characteristics:
-Large cells with abundant ground-glass cytoplasm
-Vesicular nuclei with prominent nucleoli
-Distinct cell borders
-Moderate to high mitotic activity.
Architectural Patterns:
-Sheets of cells with ground-glass cytoplasm
-Minimal stroma between cells
-Solid growth pattern predominant
-Focal necrosis may be present.
Grading Criteria:
-High-grade malignant phyllodes tumor
-Marked nuclear atypia
-High mitotic rate
-Ground-glass cytoplasm characteristic feature.

Immunohistochemistry

Positive Markers:
-Cytokeratins positive (broad spectrum)
-EMA positive
-CEA positive
-Periodic acid-Schiff (PAS) positive (diastase resistant)
-Epithelial component: CK7+, EMA+.
Negative Markers:
-Vimentin negative
-S-100 negative
-Melanoma markers negative
-Neuroendocrine markers negative
-Lymphoid markers negative.
Diagnostic Utility:
-PAS positivity (diastase resistant) characteristic
-Cytokeratin positivity confirms epithelial nature
-CEA positivity supportive.
Molecular Subtypes:
-Classic glassy cell carcinoma
-Glassy cell carcinoma with squamous features
-Mixed glassy cell and other carcinoma types.

Molecular/Genetic

Genetic Mutations:
-TP53 mutations common
-KRAS mutations possible
-PIK3CA alterations
-Complex chromosomal alterations
-Specific metabolic pathway alterations.
Molecular Markers:
-p53 overexpression common
-High Ki-67 proliferation index
-PAS-positive material in cytoplasm
-Altered glucose metabolism.
Prognostic Significance:
-TP53 mutation associated with aggressive behavior
-High Ki-67 indicates rapid proliferation
-Size and grade important prognostic factors.
Therapeutic Targets:
-Conventional chemotherapy
-Targeted therapy based on molecular profile
-mTOR pathway inhibitors
-Metabolic targeting approaches under study.

Differential Diagnosis

Similar Entities:
-Primary breast glassy cell carcinoma
-Metastatic glassy cell carcinoma to breast
-Clear cell carcinoma
-Glycogen-rich carcinoma
-Lipid-rich carcinoma.
Distinguishing Features:
-Phyllodes with glassy cell: Leaf-like areas, PAS+
-Clear cell carcinoma: Different cytoplasmic appearance
-Glycogen-rich: PAS positive, diastase sensitive.
Diagnostic Challenges:
-Recognition of glassy cell features
-Distinction from other clear cell tumors
-Assessment of phyllodes components
-PAS staining interpretation.
Rare Variants:
-Glassy cell carcinoma with squamous differentiation
-Mixed glassy cell and adenocarcinoma
-Glassy cell with neuroendocrine features.

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Specimen Information

[specimen type], measuring [size] cm in greatest dimension

Diagnosis

[diagnosis name]

Classification

Classification: [classification system] [grade/type]

Histological Features

Shows [architectural pattern] with [nuclear features] and [mitotic activity]

Size and Extent

Size: [X] cm, extent: [local/regional/metastatic]

Margins

Margins are [involved/uninvolved] with closest margin [X] mm

Lymphovascular Invasion

Lymphovascular invasion: [present/absent]

Lymph Node Status

Lymph nodes: [X] positive out of [X] examined

Special Studies

IHC: [marker]: [result]

Molecular: [test]: [result]

[other study]: [result]

Prognostic Factors

Prognostic factors: [list factors]

Final Diagnosis

Final diagnosis: [complete diagnosis]